Precision evaluation of the Ga-71(nu(e),e(-)) solar neutrino capture rate from the (He-3,t) charge-exchange reaction

A precision measurement of the Ga-71(He-3,t)Ge-71 charge-exchange reaction was performed. By using a rather complete set of theoretical form factors to describe the cross-section angular distributions over a large angular range, the Gamow-Teller strength distribution up to the effective neutron-separation energy in Ge-71 was extracted. The data and the analysis constrain the Ga-71(nu(e),e(-)) solar neutrino rate in a neutrino nonoscillation scenario. For nonoscillating neutrinos we report a solar neutrino capture rate of 122.4 +/- 3.4(stat) +/- 1.1(sys) SNU, which is lower than the presently accepted value of 132 +/- 18 SNU, though not in disagreement given the quoted errors.